Liquid dispensers for jetting fluid materials such as solder paste, conformal coatings, encapsulants, underfill material, and surface mount adhesives, are known in the art. These dispensers generally operate to dispense small volumes of fluid material to a substrate by rapidly contacting a valve seat with a valve member to create a distinct, high pressure pulse that ejects a small volume of fluid material from the dispenser. With repeated use, however, the contact between the valve member and the valve seat can cause wear or damage to either or both of those components in a manner that alters the dispensing characteristics of the dispenser. In addition, some fluid materials can contain particles, such as non-liquid components. The particles may be crushed between the valve element and the valve seat and this can damage the particles, or the valve element and valve seat, or both.
Therefore, a need exists for improvements relating to dispensers for jetting fluid materials.